Where are you going to, from where? I like I-77 through VA, it's one of my favorite drives, towing a large trailer, driving a bus or driving a car. You get to go through some nice tunnels, and great scenery. Some hills but nothing serious. Your Duramax won't notice...
Brian
2005 F250 Supercab, Powerstroke, 5 speed automatic, 3.73 gears.
20 ft race car hauler, Lola T440 Formula Ford, NTM MK4 Sports Racer
1980 MCI MC-5C highway coach conversion
2004 Travelhawk 8' Truck Camper